Japanese Patent No. 88002418 reports the synthesis of 7,7-dihydro-7-hydroxy(perfluoro-3-oxahepten-1) by chlorinating the methyl ester of perfluoro(3-oxa-1-heptenoic acid), reduction of the chlorinated product with NaBH.sub.4 to give the corresponding alcohol, and then reaction of the alcohol with zinc metal to regenerate the vinyl ether, which is the desired product. It is reported that this compound can be free radically copolymerized with at least one other fluorinated monomer, and optionally non-fluorinated monomers, to form useful polymers.
U.S. Pat. No. 4,564,717 reports the synthesis of compounds of the formula CF.sub.2 .dbd.CF(CF.sub.2).sub.m (CH.sub.2).sub.n OH wherein m is an integer from 0 to 10 and n is an integer of 1 to 4. Among the methods of preparation described, is the reduction of the compound CF.sub.2 X.sup.1 CFX.sup.2 CF.sub.2 COOR (sic) wherein R is alkyl and X.sup.1 and X.sup.2 are chlorine or bromine, by various reducing agents including alkali metal borohydrides. The olefin is then produced by dehalogenation of the alcohol with a metal such as zinc. In essence, in both this and the previous reference, the double bond has been "protected" by halogenating it (with chlorine or bromine) before the reduction step, and dehalogenating after the reduction step.
European patent application No. 135,917 discloses copolymers of vinylidene fluoride with a compound of the formula CF.sub.2 .dbd.CF(CF.sub.2).sub.m (CH.sub.2).sub.n OH where m is 0 to 10 and n is 1-4, and optionally another fluorinated termonomer. Polymers of hydroxy containing fluorovinyl ethers are not mentioned.
European patent application No. 199,138 reports preparation and polymerization (with other fluorine containing olefins) of the compound CF.sub.2 .dbd.CFO(CF.sub.2 CFYO).sub.n (CF.sub.2 CF.sub.2 CH.sub.2 O).sub.m CF.sub.2 CF.sub.2 CH.sub.2 X, wherein X is hydrogen or halogen, Y is fluorine or --CF.sub.3, m is an integer of 0 to 5 and n is 0, 1 or 2. No mention is made of a hydroxy group being present.
It is one object of the present invention to provide a simplified method for the production of hydroxy containing fluorovinyl compounds by the alkali metal borohydride reduction on the corresponding esters. It is an additional object to conduct the reduction process so protection of the double bond, as by halogenation, is unnecessary.
A further object of the invention is to homopolymerize hydroxy containing fluorovinyl ethers using anionic catalysts. It is an additional object to disclose polymers resulting from the polymerization of hydroxy containing fluorovinyl ethers.
Finally, it is also an objective of this invention to provide certain novel hydroxy containing fluorovinyl ethers and their copolymers with selected monomers.
These and other objects are achieved by the invention disclosed in the below specification and in the appended claims.